Gripper-tensioning mechanism for presses



' I 1,628, 60 May 1927' F. s. ENGLISH :1- AL 9 GRIPPER TENSIONING MECHANISM FQRTRBSSBS I Filed May 6. 1925 5 ShQOtE-ShOQf. 1

lllllll May 17 1927.

Filed May 6, 1925 s smu -sheet 2 1,628 960 May 1927' F. s. ENGLISH ET AL GRIPPER TENSION IN G MECHANISM FOR PRESSBS' May 1-7 1927. 1,628,960

F.'$. ENGLISHv ET AL GRIPPER mus ioume uscrmmsu' FOR PRESSBS ifilecy llay 6, 1925 J 5 Sheets-Sheet 5 II a I avweutoz QMJ add? (f Patented May 17, 1927.

UNITED STATES:

ENT QFFIC E;

FRED ENGLISH AND THOMAS L. PERRY, OF, NEW LONDON, CONNECTICUT, ASSIGNOBS TO BABCOCK PRINTING PRESS MANUFACTURING COMPANY, OF NEW LONDON, vCON NECIIQUIT, A CORPORATION- OE CONNECTICUT.

GRlPPER-TENSIONING MECHANISM FOR PRESSES.

' Application filed May 6,

The present invention relates to mechanism for holding the grippers upon the sheet and the same is adapted for use in printing presses as well as cutting and creasing presses. In present practice it is. customary to provide a shaft which is carrled'by the impression cylinder of a press and on the shaft are mounted a series of curved fingers, commonly called grippers, which impinge against the forward edge of the sheet which is to be printed or cut and creased, pressing the edge of the sheet against the forward or leading edge of the impression portion of the cylinder. Generally the grippers are closed on the sheet by spring action, and they are opened by means of a cam through a lever action which turns the gripper shaft. When the grippers first act on the sheet the latter is stationary and the inertia of the sheet must be overcome practically instantly. This places a heavy burden upon the grippers when the sheet is first started, and requires much greater holding force than is afterwards necessary to carry the sheet around with the impression cylinder. If there is any slippage between the sheet and the grippers while the sheet is starting from the dead stop position, this will affect the register of the press. The object of the present invention is to provide means for placing an additional pressure or tension upon the grippers while the inertia of the sheet is being overcome, and this pressure may be continued during any portion of the revolution of the cylinder, although in practice it has been found necessary to apply this additional pressure only during the starting of the sheet and, fora very short period thereafter. If the ordinary springs usually employed for closing the grippers upon the sheet are made sufliciently stiii to provide the extra pressure required during the starting of the sheet, there is difficulty in opening the grippers to deliver or take the sheet and the gripper operating mechanism in such case is subject to rapid wear. In the present case we have shown means separate from the ordinary means for pressing the grippers, which places an additional or auxiliary pressure upon the grippers at the moment the latter are closed upon the sheet. Another 1925. Serial No. 28,355.

Figure 2, is a sectional view of partof the cylinder showing parts of our improvements,

Figure 3 is a plan View of the parts shown in Figure 2, v

Figure t is a front elevation showing both the ordinary gripper mechanismand our improvements,

Figure 5 is a detail View of the parts enlarged showing the details of the segmentand gear,

Figure 6 is a plan view of the same parts,

Figure 7 is an enlarged detail view showing the auxiliary spring step,

Figure 8 is a plan view of the same parts Figure 9 is a sectional view of the impression cylinder showing our invention in modified form.

Figure 10 is a plan view of the same, and Figure 11 is an enlarged sectional view of the principal parts of the modified form of device. i

In Figures 1 to 4 inclusive we have shown the impression cylinder 1 such as is employed in a two-revolution printing press, and it is'to be understood that this may represent the impression cylinder of a cutting and creasing press. The sheet engages around the impression surface of the cylinder to be printed or cut and creased in cooperation with the flat form or circular form on the bed or type cylinder, these latter parts not being represented in the drawings. At 2 we have shown the end of the feed table which is arranged adjacent the sur face of the impression cylinder 1 and from which are fed the sheets over the forward edge of this feed board into position to be taken by the grippers on the impression cylinder. It may be here stated that the mechanism described herein may be used in connection with any other cylinder on which the sheet travels and the principle of operation will be the same. At t we have shown the shaft which extends longitudinally of the cylinder and it is mounted on a suitable bracket 1 of the cylinder and it is known as the gripper shaft and it carries a number of grippers 5, of which only one is shown in the drawing, these grippers being secured to the shaft in such position that the tips of the grippers will impinge the sheet against the leading edge of the impression portion of the cylinder. The ordinary device for operating these grippers to grip and release the sheet comprises the crank (i which is fixed to the shaft 4 beyond the end of the cylinder; anl this crank carries an anti-friction roller 7 which is acted upon by a cam 8 which is secured to the stationary portion of the press frame so as to act on the roller 7 in proper time relation. The shaft l is rocked in order to maintain the roller 7 against the cam 8, by means of the spring 9 which surrounds the spring rod 19. One end of the spring 9 abuts against the spring step 11 on the cylinder and the other end presses against a collar on the rod 10 the latt'er .being pivoted to the segment 13 at 12, and the segment 13 is pivoted to the cylinder at the point 12 This segment 13 is provided with segmental gear teeth which mesh with a segmental gear 14; attached to the shaft 4. The expansive action of the spring 9 acting through the rod 10 serves to swing the segment 13 and this, acting through the gear 14 tends to rotate the shaft 4- in the direction necessary to maintain the roller 7' against the edge of the cam 8. In the ordinary operation of this device, when the cylinder revolves in the direction indicated by the arrow the roller 7 comes into contact with the cam 8 first at the point 15, and the roller is then moved downwardly, which serves to openthe grippers, and then the roller 7 rises just before leaving the cam 8 and at such time the spring 9 serves to close the grippers 5 upon the leading edge of the sheet. These devices are all commonly used in the art and have been for many years. If the spring 9 is set up very tight in order to press the grippers 5 very hard against the sheet there will be considerable wear between the roller 7 and the earn 8, particularly at the point 15 where these parts first come into contact, and it has heretofore been impossible to place the desired pressure on the spring 9 on account of the wear and tear on these parts.

In our device for placing additional pressure upon the grippers we employ, as far as possible, parts of the ordinary gripper operating mechanism. In the device shown in Figures 1 to 8 We have shown an auxiliary gear 16 attached to the gripper shaft 1 and there is a segment 17 having teeth which mesh with the teeth of the gear 16 and this segment is pivoted on the stud 18 which is mounted on a lug 19 on the cylinder. There is a compression spring 29 surrounding the rod 21 and the latter is pivoted by means of a stud 22 to the segment 17. -The compres sion action of the spring 20 acting through the rod 21 rocks the segment 17 and acting through the ear 16 it causes a revolving pressure upon the gripper shaft 1 in addition to the pressure which is exerted through the ordinary device, including the spring 9 as above described.

One end of the spring 20 abuts against a movable spring step which includes a step member 23 with which the end of the spring directly engages and this step is mounted on a lever arm 2% which is fastened to a shaft 25, the latter being arranged to rock in the bearings 26 and 2? of the cylinder. On the end of the shaft 25, outside of the cylinder, there is a lever arm 28 the free end of which carries a roller 29 which engages with a cam 30 which is stationarily mounted on a portion of the frame of the press, as, for instance, to the part 31 of the frame. There is a stop bolt 32 secured to the lever arm 28 and it is adapted to engage the hub of the cylinder to limit the swinging of the lever 2%, 28 during the time that the roller 29 is disengaged from the cam 30.

Operation.

About the time the grippers are to be closed upon the sheet through the action of the spring 9 by the ordinary closing devices, the roller 29 rides onto the higher part of the cam 30 and this rocks the shaft 25 and through the lever arm 24: the spring step 23 is moved to place the spring 20 under compression, and the action of this spring, transmitted through the segment 17 and the gear 16 to the shaft 4, causes a pressure or tension to be placed upon the grippers in addition to that produced through the action of the spring 9, and this action takes place when the grippers first engage the sheet and when the sheet first starts to move with the cylinder, which is the time during which the inertia of the sheet has to be overcome, requiring extreme pressure of the grippers upon the sheet. Subsequently the roller 29 runs off the high portion. of the cam 30 and the pressure of the spring 20 is released, and when this condition obtains the grippers may be opened by the cam 8 or any additional cams employed for that purpose. as readily as if our device were not used.

The present invention is susceptible to various modifications and in Figures 9 to 11 we have shown another form of the invention. In this form we have shown the same grippers 5 mounted on the shaft 4,

the same as in the first'forih. On this shaft there is fixed a notched disc 34 and-there is a pawl 35 pivoted upon the stud 36 so that the freecend of he paw'l ejngages the shoulder 48 ofthe notched disc 34. The pawl hasa pivotal motion upon the stud andthe latter is s ired to a lever 37 which is fixed to th 1 a 38* mounted in the cylinder to esc llatein the bearings 39' and 40'. Outside of ieeylinder there is a lever arm 54securedio the shaft 3Sand it carriesa roller 4O which is adapted to be acted uponby a cam 41 stationari-ly fixed toa portion of e'press frame. This roller 40 is held pressed against the cam' by means of a spring 43 which surrounds the rod 44. One end of the spring presses against the lever 37 while the other, presses against a spring step 46 attached to the cylinder at 47. The pawl 35 is forced against the shoulder 48 by means of a compression spring 49 which surrounds the rod 50 and is compressed between the spring step 51 which is part of the lever 37,'and against the under side of the pawl 35. There are nuts 52 and 53 at opposite ends of the rod 50 and by adjusting these nuts the pawl 35 may be regulated in position to engage the shoulder 48.

In the drawings we have shown this deturned back from the position shown in the drawings until the roller 40 is engaged with the high portion of the cam 41, at this time the grippers 5 will be slightly open to allow the forward edge of the sheet to be fed to the forward edge of the impr ssion portion of the cylinder. At this time the lever 37 will be rocked slightly anticlockwise in Figure 9 so that the point of the pawl 35 will be disengaged from the shouldrr 48 of the disc 34 and it will be slightly below the shoulder 48. As the cylinder proceeds to move to the left from the posit on above described, the roller 4O will finally more onto the lower portion of the cam 41 and the point of the pawl 35 will more slightly clockwise and also upwardly in relation to the disc 34 so that it will come intocoiitact with the shoulder 48 just before or at the instant the, grippers are pressed against the sheet by the ordinary gripper closing mechanism, .which latter will be the same in this construction as in the first described form. Any slight irregularity of adjustment of the parts may be c m1')ensated for througlrthe spring 49, In case the cylinder is turned baclrwardly the spring 49 will allow the grippers to be opened without inju'ry.

lAis the cylinder continues to revolve antileased so that the additional auxiliary pres sure on the shaft 4 is released at or before theti ne approaches for the opening of the grippers. In a two-revolution press the cylinder is in a raised position at the time the grippers take the sheet and it islowered at the time the grippers are opened to deliver the sheet and this rising and falling motion of the cylinder'in relation to the fixed cam 41 in itself is sufficient to throw the auxiliary mechanism outof action at the time the grippers are opened if desired, ,7

It is obvious that the still or inactive period'of the cam in both constructions can be of any convenient length so that the additional pressure on the grippers may be applied merelyffor a brief time when the sheet is taken and then immediately released, or the additional pressure may be maintained during a considerable portion of the printing cycle of the press. Themain requirement is that the additional pressure is to be exerted at the time the sheet is first taken by the grippers and until the inertia of the sheet has been overcome. both of these devices may be used on a printing press, or a cutting and creasing press, or any other form of press in which the sheet is taken by a gripper action.

Having described our invention, what we claim is:

1. In a press the combination of a cylinder, grippers thereon adapted to engage and hold a sheet for movement with the cylinder, means for operating the grippers to en gage and hold the sheet, and means for applying an auxiliary or additional closing pressure upon said grippers at the moment they are closed upon the sheet and adapted to automatically releascsaid auxiliary pressure before the grippers are opened, said auxiliary means including a spring for exerting closing pressure on, the grippers.

2. In a press the combination of a cylinder adapted to carry a sheet, grippers there on and means for closing the grippers on the sheet for holding the same, and means adapted to automatically apply an additional or auxiliary closing pressure upon the grippers at the moment the sheet is taken, and adapted to release said auxiliary pressure as soon as the sheet starts to move with said cylinder, said auxiliary pressing means including As above set forth int) a spring for exerting closing pressure on said gnppers.

3. In a press the combination of a cylinder adapted to carry a sheet, grippers thereon and means for closing the grippers on the sheet for holding the same, and means for applying an auxiliary closing pressure on the grippers including a gear on the gripper shaft, a rocking segment having teeth meshing With the said gear, a spring for rocking said segment, a lever adapted to operate said spring and a cam to operate said lever.

t. In a press the combination of a cylinder adapted to carry a sheet, grippers thereon and means for closing the grippers 0n the sheet for holding the same, and means for applying an auxiliary closing pressure on the grippers including a gear on the gripper shaft, a rocking segment having teeth mesl iug with the said gear, a spring for rocking said segment, a lever carried by said cylinder for operating said spring and a stationary cam for operating said lever.

5. In a. press the combination of a cylinder adapted to carry a sheet, grippers thereon and means for closing the grippers on the sheet for holding the same, spring tensioning neans adapted to apply an auxiliary closing pressure to said grippers, and a stationary cam for actuating said auxiliary mechanism and adapted to release the same preparatory to the opening of the grippers.

Signed at the city of New London, county of New London, and State of Connecticut, this 1st day of May, 1925.

FRED s. ENGLISH. THOMAS L. PEP-RY. 

